Biology-Cell Structure

MOVEMENT (all living things move – even plants!)

RESPIRATION (oxygen + glucose ---------carbon dioxide + water + energy)

SENSITIVITY (detecting and responding to changes in the surroundings)

GROWTH (remember an organism ‘grows’ by producing more cells)

REPRODUCTION (making more of the same - can be sexual or asexual)

EXCRETION (expelling waste products, e.g. carbon dioxide and urea)

NUTRITION (taking in and using food)

An organism having cells with a true nucleus and membrane bound organelles.

Nucleus-

• Contains genetic information that can be transmitted to the next generation
• Controls activities of the cell

Nucleolus-

• Produces ribosomes

Nuclear Envelope-

• Contains the genetic material
• Has nuclear pores which allow communication between the nucleus and cytoplasm by allowing molecules to enter / leave the nucleus e.g. mRNA leaves the nucleus

RER-

• Protein synthesis & transport

SER-

• Lipid synthesis & transport

Golgi Apparatus-

• Receives proteins from the RER / ribosomes
• Production of vesicles / packaging proteins
• Modification of / processing of proteins (e.g. adding carbohydrate)
• Production of lysosomes

Ribosomes-

• Protein synthesis
• Translation

Mitochondria-

• Aerobic respiration (C6H12O6 + O2 --------CO2 + H2O)                     
• Production of ATP
• Release energy

Lysosomes- 

• Contain / release hydrolytic / digestive enzymes
• Digest / break down  organelles / foreign objects / toxins / cells / pathogens
• Apoptosis

Chloroplasts-

• Photosynthesis
• CO2 + H2O ----- C6H12O6 + O2

Plasma membrane-

• Controls entry/exit of substances into/out of the cell
• Acts as a barrier separating the cell contents from the environment

Centrioles-

• Formation of spindle fibres during cell division

Flagella-

• Movement of cell

Cilia-

• Wafts mucus and bacteria trapped within away from lungs

Cytoplasm-

• Site of chemical reactions

Cell wall-

• Gives cell shape / strength / support
• Prevents bursting
• Fully permeable

Vacuole-

• Storage of salts / sugars / pigment
• Provides turgor support / controls water potential

An organism having cells without a true nucleus or membrane bound organelles.

Nucleoid DNA-

• Contains essential genetic information that can be transmitted to the next generation
• Controls activities of the cell

Plasmid-

• Contains beneficial genetic information, e.g. codes for proteins that confer antibiotic resistance on the bacteria
• Can be copied and passed to other bacterial cells regardless of strain

Mesosome-

• Aerobic respiration (C6H12O6 + O2---------- CO2 + H2O)                     
• Production of ATP& Realse energy
  

Slime Capsule-

• Protection from dehydration
• Contains hydrolytic enzymes for protection from engulfment from WBCs

Eukaryotic                                                 VS                                    Prokaryotic

True nucleus                                                                                 No true nucleus

DNA associated with histone proteins                DNA is ‘naked’ / not associated with histones

Linear DNA                                                                                Circular DNA

Membrane bound organelles present

(e.g. SER, RER, Golgi apparatus)                            No membrane bound organelles present

Ribosomes larger (80S/22nm)                                          Ribosomes smaller (70S/18nm)

Larger cell size (20-40 μm)                                               Smaller cell size (0.5-5μm)

Cellulose cell wall (plants only)                                              Peptidoglycan cell wall

No plasmids                                                                                    Plasmids

Mitochondria                                                          

Both have:
An outer membrane
An inner membrane
Inter membrane space
Ribosomes and DNA  
ATP synthase enzymes / Stalked particles
A luid ‘cytoplasm like’ centre

Differences   - Mitochondria                                                          - Chloroplasts

Function = aerobic respiration                                     Function = photosynthesis
DNA and ribosomes for synthesis of proteins required for respiration                                          DNA and ribosomes for synthesis of proteins required for photosynthesis
Fluid ‘cytoplasm like’ centre = matrix                       Fluid ‘cytoplasm like’ centre = stroma
No thylakoid membrane           Third membrane within stroma = thylakoid membrane             
Folded inner membrane                                                      Inner membrane not folded
No starch grain present                                                         Starch grain present

Division of labour- Any system where different parts perform specialised functions, each contributing to the functioning of the whole, e.g. protein production and secretion.                  Protien Synthesis-
The proteins are moved to the Golgi apparatus
Where they are processed / chemically modified
And packaged into vesicles
The vesicle is then moved to the plasma membrane
Where it fuses with the plasma membrane
The proteins are then released by exocytosis                

Cytoskeleton- The network of protein fibres and microtubules found within the cell that gives structure to the cell and is responsible for the movement of many materials within it.         

Two types of protein fibre make up the cytoskeleton:

Actin- These are fibres like the protein fibres found in muscle cells. 

Role:  White blood cell movement, Organelle movement.             

Tubulin- These protein fibres form cylinders called microtubules.

Role:  Movement of a cell through liquid,Waft a liquid past the cell,Organelle / Chromosome movement.

• Provides strength / stability / support to the cell
• Determines shape / moves membrane for endo / exocytosis
• Movement of organelles / RNA / protein / chromosomes / chromatids
• Movement of flagella for cell movement
• Movement of cilia to move mucus containing bacteria etc
• Attachment to / hold organelles in place
• Make up centrioles / spindle fibres

Flagella- Few and long in length, called undulipodia in eukaryotes. Associated with locomotion i.e movement of the whole cell, such as Sperm.

Cilia- many and shorter in length, move in a wafting motion. Also associated with locomotion but the wafting motion of cilia moves substances such a mucus across the cell surface. This can be seen in ciliated epithelium tissue lining the bronchioles.

They can move as they use energy from ATP.

They both have the same structure which is called the 9+2 structure, this is because

• both contain 9 microtubles& 9 pairs of these are arranged in a circle
• 2 form the central bundle